Catalytic And Sensing Properties Of Composite Materials Based On Conducting Polymers Loaded With Nanoparticles

Nanocomposites have gradually become a hot research topic in recent years. Conductive polymers, with high conductivity and good stability, have been widely applied in the preparation of nanocomposites. This work fabricated novel electrochemical sensors, based on conductive polymers loaded with nanoparticles modified electrodes, for the detection of small molecules related to some deseases, providing effecitive assistance for the diagnosis and clinic treatment of cancers. The main contents of this thesis are summarized as follows:(1) Copper-cobalt bimetal nanoparticles(Cu-Co) have been electrochemically prepared on glassy carbon electrodes(GCEs), which were electrodeposited with conducting polymer nanocomposites of poly(3,4-ethylenedioxythiophene)(PEDOT) doped with carbon nanotubes(CNTs). Owing to their good conductivity, high mechanical strength, and large surface area, the PEDOT/CNTs composites offered excellent substrates for the electrochemical deposition of Cu-Co nanoparticles. As a result of their nanostructure and the synergic effect between Cu and Co, the Cu-Co/PEDOT/CNTs composites exhibited significantly enhanced catalytic activity towards the electrochemical oxidation of nitrite. Under optimized conditions, the nanocomposite-modified electrodes had a fast response time within 2 s and a linear range from 0.5 to 430 μM for the detection of nitrite, with a detection limit of 60 n M. Moreover, the Cu-Co/PEDOT/CNTs composites were highly stable, and the prepared nitrite sensors could retain more than 96% of their initial response after 30 days.(2) A novel electrochemical sensor for hydrogen peroxide(H2O2) was developed based on electrochemically deposited Prussian blue(PB) nanoparticles doped PEDOT. The prepared PEDOT/PB composite was composed of PEDOT wrapped PB nanoparticles, where the conducting polymer PEDOT could not only protect the PB to ensure high stability, but also connect various PB to enhance electron transfer. Owing to the excellent conductivity of PEDOT and unique electrocatalytic activity of PB, the PEDOT/PB modified electrode exhibited outstanding catalytic activity toward the electrochemical oxidation of dopamine and the electrochemical reduction of H2O2. Under optimized conditions, the PEDOT/PB nanocompositemodified electrodes had a fast response time within 4 s and a linear range from 0.2-187 μM for the detection of DA, with a detection limit of 56 n M. The H2O2 sensor could be used for the detection of H2O2 over concentrations ranging from 0.5 to 839 μM, with an extremely low detection limit of 0.16 μM(S/N = 3). Moreover, the developed sensor also demonstrated excellent reproducibility, selectivity and long-term stability, showing great promise for the fabrication of electrochemical sensors and H2O2 related biosensors.(3) Prussian blue nanoparticles filled carbon nanotubes(CNTs-PB) were prepared by a simple method,and a novel electrochemical sensor was developed based on electrochemically deposited CNTs-PB nanocomposites doped PEDOT. The prepared PEDOT/CNTs-PB modified electrode was used for the detection of ascorbic acid(AA), and it exhibited high and stable electrocatalytic activity for AA oxidation. The PEDOT/CNTs-PB nanocomposites-modified electrodes had a fast response time(within 4 s) and a linear range from 0.3-430.3 μM(R2 = 0.9981) for the detection of AA, with a detection limit of 80 n M. What’s more, the developed sensor also demonstrated excellent reproducibility, good selectivity and long-term stability.